Folding machine and control therefor



y 1946- J. E. PRESTON FOLDING MACHINE AND CONTROL THEREFOR Filed March 27, 1942 6 Sheets-Sheet 1 a a8 3 xx; 5 v Q\ O 0 re mm 8 3 Q X 9 mm in mm N w w s m um m m E E m W 0 Y B omhm QN O May 28, 1946. J. E. PRESTON FOLDING MACHINE AND CONTROL THEREFOR Filed March 27, 1942 6 Sheets-Sheet 2 FIG-3 FIG-5 iNi/ENTOR JOHN E. PRESTON BY #54 ma ATTORNEYs FIG.'6

y 8, 1946. J. E. PRESTON FOLDING MACHINE AND CQNTROL THEREFOR Filed March 27, 1942 6 Sheets-Sheet 3 I'll INVENTOR BY JOHN E. PRESTON ATTQRNEY May 28, 1946. J. E. PRESTON FOIJDING MACHINE AND CONTROL THEREFOR 6 Sheets-Sheet 4 Filed March 27, 1942 IOI FIG.- IO

' INVENTOR BY JOHN E. PRESTON 4 MW ATTORNEYS y 1946- J. E. PRESTON 2 ,401,103

FOLDING MACHINE AND CONTROL THEREFOR Filed March 27, 1942 6 Sheets-Sheet 5 124 l I22 I21 I23 12s a w I29 I6 I20 v "a? I26 I I 0 0w H-HL I I o TJF a I 0 0 A l a us I2 n7 FlG.-|l

|O7 us I m n2 ATTORNEYS May 28, 1946. J. E. PRESTON 2,401,103

FOLDING MACHINE AND CONTROL THEREFOR Filed March 2'7, 1942 6 Sheets-Sheet 6 INVENTOR JOHN E. PRESTON ATTORNEYS Patented May 28, 1946 FOLDING MACHINE AND CONTROL THEREFOR John E. Preston, Cincinnati, Ohio, assignor to The American Laundry Machinery Company, Cincinnati, Ohio, a corporation of Ohio Application March 27, 1942, Serial No. 436,466

1 4 Claims.

This invention relates to folding machines and to the control apparatus or devices therefor. It has more particular relation to machines for folding small fiat articles made of any material,

- such as paper sheets, or more or less limp articles made of textile fabrics, for example, towels, pillow slips or the like.

One object of the invention, is generally to improve the folding mechanism for producing both longitudinal and cross folds, not only by simplification thereof and of its controlling parts, but also in a manner to secure more certain and accurate results and to enable various types of fold to be produced without undue complication in the mechanism.

A further object of the invention is to provide improved longitudinal folding devices which prevent dropping or rolling of the edges of the article as they are turned in, and whichdetermines the final side edges by a creasing operation durirw longitudinal folding.

A further object is to provide an improved yieldable mounting for the ridin plate around which the articles are folded during the longitudinal folding operation, thereby making said plate self-accommodating to extra thickness or unevenness in the work. Still another object of the invention is to provide an improved construction and arrangement of cross folding blade by means of which the inertia of rest is more easily overcome and the blade is started and is moved the more readily.

Still another object is to provide improved control devices for use in the production of multiple folds, enabling such folds to be made in certain instances with one edge of the article turned in or wrapped within the other folds or plies, thus presenting the work in neatly ar-v omitted to expose interior operating mechanism;

Fig. 2 is a plan view of the machine shown in Fig. 1; Fig. 3 is an end elevation, illustrating the upper longitudinal folding mechanism shown in Fig. 1; Fig. 4 is a detail longitudinal section on the line 44, Fig. 3; Fig. 5 is a sectional elevation on the line 5-5, Fig. 2; Fig. 6 is a cross section on the line 6-6, Fig. 2; Fig. 7 is an enlarged longitudinal sectional elevation, on the line '|--1, Fig. 2; Fig. 8 is a detail sectional elevation of the cross folding blade mechanism, on the line 88, Fig. 7; Fig. 9 is a sectional elevation on the line 99, Fig. 1; Fig. 10 is an enlarged detail fragmental view of the stacker counting mechanism, looking in the direction of the arrows Ill-I0, Fig. 9; Fig. 11 is an enlarged side elevation, corresponding to Fig. 1, of the clutch mechanism; Fig. 12 is a detail section on the line l2--|2, Fig. 11; Fig. 13 is a detail section on the line l3 -l3, Fig. 12; Fig. 14 is a diagram, illustrating the circuits for the timing and measuring control devices; and Fig. 15 is a detail diagrammatic view of certain switch mechanism.

In some respects, the machine of the present invention is capable of wide use and for a variety of purposes. Generally speaking, it embodies means for performing an operation with respect to each of a series of articles differing in length, means for producing relative movement between such performing means and the article, and time delay relay means operating over a period of time while such relative motion is going on for delaying and determining the time and place of performance of such operation with respect to the article.

My copending application for Sequence timer and measuring control, Serial No. 136,465, filed of even date herewith, illustrates, describes and claims various embodiments of the broad invention here involved. According to that disclosure, each of a series of articles maybe measured and after a preselected time delay period. its length may be indicated or recorded. Or, each of a series of articles varying in length may be out or punched or indented at one or more points in proportion according to its total length, such as at its middle point, or at a point one-third from its end, or at several points. Or, sheets of paper of varying length may be imprinted, or some other operation may be performed upon them, at one or more points proportioned according to their length.

For convenience, and in no sense of limitation, I have here illustrated as one suitable embodiment of the invention a machine for folding relatively small more or less limp fabric articles, such as pillow slips, towels or the like, although the invention is understood not to be so limited but to include all mechanism within the scope of the claims appended hereto. The machine illustrated first will be described in detail, folare delivered or laid out and which accomplishes their introduction to the conveying and longitudinal folding mechanism;

Longitudinal folding mechanism F which produces one or more folds extending longitudinally of the article;

One or more transverse folding devices G which produce cross folds in the article; and

A collecting or stacking device H where the product of the machine is collected in orderly piles ready to be removed.

All of the foregoing instrumentalities are more or less automatically controlled in manner and by means to be described.

The machine shown embodies a frame In, at one end of which (the left hand end in Fig. 1) is supported the feeding device E, and which also supports the longitudinal folding apparatus F, the cross folding mechanism G, and the stacking mechanism H.

The feeding device The feeding device E includes conveying ribbons ll travelling over front and rear rolls l2, 13, Figs. 1 and '7, with the top run moving toward the rear end of the machine or away from the operator. These ribbons are driven by a sprocket H on the shaft l5 of one of the rolls connected by a chain I6 with a sprocket on a shaft l'l provided with a pulley l8 connected by belt 19 to a pulley on the shaft of a suitable driving motor 20.

Roll shaft 2| has fixed thereto a pair of smaller rolls 22 which drive a set of ribbons 23 running over another roll 24 supported in suitable bearing brackets at the feeding end of the machine, and roll 24 drives another pair of ribbons 25 running over an idle roller 26. The idlers Hand 28, suitably mounted, provide belt tightening means. On account of the larger size of rolls I2 with respect to the rolls 22, the ribbons 23, 25 travel at a slower speed than the ribbons H, thereby producing spaces or gaps between successive articles when. the feeding device formed by the belts 23, 25 delivers the articles successively to the conveying ribbons ll. These conveying ribbons carry the articles to and through the longitudinal folding mechanism, and thence to the cross folder, as will later appear.

Long tudinal folding mechamsm The longitudinal folding mechanism F includes two side wings 30, 3|. Figs. 3 and 5 illustrate how these wings consist of metal sheets rolled or bent upwardly and inwardly progressively, as illustrated at Ma and Ma. As the article advances with the conveying ribbons II the outer edge portion of its right hand part (looking forward) is rolled over by the right wing am to lie upon the middle part of the article and later its left part is rolled over by the left wing 30a to be superposed upon the already folded right part. To hold the middle part of the article flat and straight, it is held down by 'a riding plate 32,

' the riding plate 32.

which rides upon the moving article and upon the upper surface of which the right edge of the article is folded. This plate, in the present machine, is made thin and it is also yieldable so as to offer light downward pressure and yet enable the plate to rise slightly and accommodate itself to any multiple or extra thickness of the article, as at hems. It also is electrically conductive, forming part of the circuits, as will later appear. For this purpose the riding plate 32 is carried by a support consisting of a thin flexible metal plate 32a mounted on support brackets 33 but insulated from other parts by washers 32b (Figs. 3 and 4). The folding line for the right hand part of the article is determined by the right hand edge of The outer edge portion of the left hand part is rolled over by the wing 30 upon a second riding plate 34, the forward edge of which is supported by the upper face of the folding wing 3!. The folding line for the left part of the article is determined by the left hand edge of the plate 32 and as the folding operation proceeds the respective right and left folded parts are separated from each other and from the middle part of the article by the riding plates 32, ll.

According to the present invention the earlier portions 30b, 3"), of the folding wings, where they are first engaged by the article, are progressively more and more inclined to the horizontal plane, as shown in Fig. 3. This simple elevation of these folding plates, out of the horizontal to an inclined position, accomplishes the two folds with more certainty. The inclination is in favor of the turning over or rolling movement produced by the folding wings along the outer edge portions of the right and left parts of the article and materially assists their operation.

Usually a portion of the folding plates is enclosed by a cover plate 35 hinged at 36 to enable it to be readily lifted up when desired.

To further assist in the longitudinal folding operation, and to establish and maintain proper folding lines, I preferably provide means for grooving the work as it proceeds. This means includes a pair'of V-edged disks 31 mounted on a shaft 38 carried by arms 39 fixed to a shaft I supported on the bracket arms 33. Also fixed to shaft 40 is one end of a coil spring 50, the oppodirection, Fig. 4, to cause them to press the work into engagement with V-grooved lower rolls ll, Figs. 1 and 6, lying beneath the work. The rollers II are supported on a shaft 42 carried by the frame, said shaft also being provided with suitable driving means, such as a sprocket 43 connected by chain 44 to a sprocket 45 or roll shaft l2.

With the foregoing arrangement the grooved rollers are driven along with the receiving belts 23, 25 and the conveyor belts I I, and in timed relation with the travelling work. The disks lie close to and in line with the edges of the riding plate 32 and with it determine the fold lines. Their purpose is to pre-crease each article, along the proper fold lines, just as it reaches the riding plate and begins to be turned up by the inclined portions 30b, 3") of the folding wings. The rollers also assist, of course, in causing feeding advance of the article.

First cross folding mechanism Each article, when it leaves the longitudinal folding mechanism, is subjected to one or more cross folding operations. The first cross fold is produced by cross folding mechanism shown in detail in Figs. 7 and a. It includes a folding blade 51, lying in a vertical plane above the work and arranged to engage each article at a preselected point along the length thereof and move it downwardly and tuck it into engagement in the bite between a pair of pinch rolls, one of which, I3, supports the feeding belts II, and the other of which, 58, is supported in floating bearings 59, Fig. 1, one at each end. Springs 88 bias roll 58 toward roller I3. When the article reaches the bite between these rolls it is carried through between them and thus is cross folded, and the folding blade then retires for another operation.

The folding blade 51 lies and moves in a vertical plane, being guided for vertical movement in a suitable frame 8|. Springs 82 bias it upwardly, and it is moved downwardlylay the armature 83 of a solenoid 81, said armature being connected by links 65 to levers 84 pivoted at 840 to the frame and connected respectively to opposite portions of the folding blade by links 89, 1.8. Downward motion of the folding blade is limited by engagement of a shoulder 83a on the solenoid armature with the solenoid housing, and a housing II is provided to enclose the mechanism.

When but a single cross fold in the article is desired, the article, when it leaves the folding rollers I3, 58, drops down to a curved conveying plate I2 along which it slides to ribbons I3 which toward the end of the curved plate extend above it and beyond its end and. which deliver the article to the belts of the stacking mechanism H, as will later appear.

Second cross folding mechanism While in some cases the articles may be sufficiently finished if cross folded but once, nevertheless the present machine is arranged to provide a second cross fold when such is desired.

The mechanism for this purpose includes a second folding blade I5 mounted on one arm 16 of Side brackets 94 also support shafts 98, 99, Fig. '7, carrying pulleys I88, I8I over which travel round belts I82, the upper run of each of which a lever pivoted at 11, the other arm I8 of which is provided with a head 18 actuated by the armature 88 of a solenoid 8|. Said folding blade is normally biased to retire by a spring 82. At the appropriate preselected time, said folding blade I5 moves forward, engages the article depending beneath the rolls I3, 58 and held in the bite thereof, and advances the article into the bite between the roll 58 and another roll 83 supported in the frame and lying beneath it. The floating bearings 59,. as shown in Fig. 1, are angularly disposed, so that the bias of spring 88 upon roll 58 provides yielding pressure of said roll against both of the rolls I3, 83. As shown in Fig. 1, the shaft of roll 83 is provided at one end with a sprocket 84, enabling it to be driven by the same belt l8 which drives roll I3. Articles subjected extends slightly above the upper surface of the lifting plate 83, when the latter is in its lower position, said lifting plate being slotted for the purpose, as shown at I83, Fig. 2.

Any article delivered by the belts I3 to the stacking device moves forward on top of the.

stacking plate 83, in its lowermost position, and into contact with the belts I82 which advance the article into the'stacking device until its leading edge engages a movable stop device I84, Figs. 7 and 10. The stack of finished articles is built up by additions to its bottom, and the rising pile is guided and supported by upstanding posts I85.

Suitable intermittently, operating mechanism is provided for operating the stacking mechanism, preferably in timed or synchronized relation with the cross folding devices before described. As illustrated, the operating mechanism includes a shaft I88 provided with a two-lobed cam I81. adapted to actuate one arm I88 of a lever pivoted at I89, the other arm II8 of which lies beneath the lower end of, and elevates, the post 92 and the lifting plate 93 carried thereby.

On shaft I88 are mounted, for rotation together or as a unit, a ratchet wheel III and a sprocket H2, the latter connected by a driving chain H3 to a small sprocket III on the main driving shaft I'I, so that the unit I I I, II2 rotates continuously. On the same shaft I86, and pinned thereto, is an operating member I I5 having two arms diametrically opposed, one of which carries a T-shaped latch lever H8, while the other carries an L- shaped lever III, arms of the two levers being cross connectedby a link H8, and the linkand lever system being biased by a tension spring H9 to engage a tooth I28 of lever II-G with the teeth of ratchet III, such operation normally .being prevented by an abutment I2| on a lever I22 pivoted at one end at I23, and at its opposite end connected to the armature I24 of an electromagnet I25. One end of alatch lever I26 normally lies behind a pin I21 on the arm II5, holding it in position with the upper arm of lever I I6 against the abutment lug I2 I, as shown in Fig. 11. Latch lever I26 is biased by a spring I28, which holds it against a stop I29. When the arm I I5 rotates (turning clockwise in Fig. 11) the pin "I21 rides beneath the lower edge of lever I26, lifts its right hand end and passes beyond it, the lever dropping into place into the position shown, ready for to a second cross folding operation between rolls 58, 83 are delivered to a curved plate 85 along which they slide to the same belts 13 before referred to, which carry them into the stacking mechanism now to be described.

Stacking mechanism 93. Side brackets 94 support pivotally, at 95,

left and right stack supporting plates 95, 97 provided with inwardly extending fingers 96a, 91a, which extend into notches in the side edges of the lifting plate 93, as shown in Fig. 2.

another operation.

The stacking mechanism operates as follows:

In the normal position of rest of the parts, shown in full lines Fig. '7, in Fig. 9 and in Fig. 11, the stack of previously folded articles rests upon the left and right fingers 98a, 91a and the lifting plate 93 is at a lower level with the belts I82 extending slightly above it. A previously folded article may be lying upon plate 93 if the machine has been in continuous operation. The parts are so timed, as will later appear, that when the folding blade 51 is again depressed to fold the next article, by energizing solenoid 61; solenoid I25 is also momentarily energized, thus raising lever I22 and releasing the lever H8 to the effect of its biasing spring II9. Dog I28 thereupon enters a recess of the ratchet wheel I I I, coupling the member I I5 to rotate with the ratchet wheel and thus turn shaft I86 and the two-lobed cam I81. Immediately upon release of lever IIG solenoid I25 is deenergized, lever I22 drops and the lug I2I assumes its original position, ready to engage a trip arm of either trip III or II1, when it next comes around, thus disengaging the dog m frbm the ratchet wheel and terminating the operation of the half revolution mechanism. During the one-half revolution of shaft I09, one of its cam lobes swings lever I03, III! and elevates post 32 and the lifting plate 93. Plate 93 carries up with it any article previously deposited upon it, adding it to the pile, and lifting the pile so that the lowermost fresh article reaches a position above the lifting fingers. The lifting plate then moves down again to its original position, and immediately receives the next article, which by the simultaneous energization of solenoid 63 has just been folded by blade 91 and has then been delivered to the stacker by one of the chutes 12 or 35. Pivotal mounting of members 99, 91 permits free upward movement of the articles, as will be readily understood. When the two solenoids 31, I25 are again energized simultaneously the same folding and stacking operations are repeated.

With such an arrangement, where the article is delivered to the lifting plate before the complete cycle of operations is completed, and lies there awaiting initiation of the next cycle by energization of the solenoids, there is no likelihood of the lifting plate rising before the article has fully entered the stacker. Morelcertain operation is thereby secured.

Counting mechanism While not essential, the stacking mechanism may be provided with counting mechanism constructed and arranged to operate as follows:

The counting mechanism is best illustrated in Figs. 9 and 10. It includes an arm Hill-mounted to rotate freely on a stub shaft I 3|. This arm carries a pawl I32 yieldingly held in engagement with the teeth of a ratchet I33. An auxiliary finger I34 is pivotally mounted on the pivot shaft 95 on which the right-hand stack supporting plate member 91 is pivoted. This finger has connected thereto a depending rod I35 sliding in a guide I36 and biased to the position shown in Fi by a compression spring I31. The lower end of rod I35 lies just above an end of the arm I30. Auxiliary finger I34 extends into the path of vertical article movement in the same manner as fingers 9111. Therefore, when the newly arrived article and plate 93 move upwardly and turn plates 96, 91 about their pivots, auxiliary finger I34 is also tilted, causing rod I35 to move downwardly and actuate arm I30, turning ratchet I33 and shaft I3I the distance of one tooth, to a new position, where it is held against return by a detent pawl I38.

Ratchet wheel I33 has affixed thereto a bar member I40, opposite ends of which extend slightly beyond the wheel periphery. During each half revolution of the wheel one end of this bar engages one arm I of a latch member pivoted on the shaft I42, rotating it counterclockwise in Fig. 10, and causing the upper end of its other arm I43 to move away from its position beneath a lug I44 on the back of the stop plate I04. Then the leading edge of the next towel or other article fed into the stacking mechanism moves beyond the lowered stop plate I04 until it engages a fixed stop plate III4a. Therefore, one towel in each group of article, corresponding to the number of ratchet teeth in one-half the circumference of ratchet I33, extends beyond the face of the stack. If the ratchet wheel has fifty teeth, for example. a short piece of every twenty-fifth towel projects beyond the face of the stack. so that the towels readily maybe taken off in multiples of twenty-five. The next time the stacking mechanism operates, an extension I45 on the lever arm IIO engages the lower end of stop I94, restoring it to its original position with its lug I44 above the lever arm I43.

Of course, this arrangement always leave; the last towel, folded, in the stacking device below the stack supporting plates, when the machine is stopped. Accordingly I provide the mechanism with a rod I46, Fig.1, connected at one end to lever I22 and the other end extending to a convenient upper position. By pulling up on this rod the trip lever H6 or I I1 may be released and the stacking mechanism caused to operate once to clear it of the last folded article.

Usually the mechanism is also provided with a totalizing counter. In the arrangement shown I provide such a counter of conventional form, indicated at I41, Fig. 10, the operating arm I" thereof being connected by a link I49 to a lug on the auxiliary finger I34, so that this totalizing counter will be actuated once for each ac tuation of the stacking device and indicate and record the number of towels folded, to check production of the mechanism.

General operation Summarizing the operation of the mechanism as a whole, described thus far, articles to be folded are delivered in succession to the feeding belts 23, 25, either manually by an operator, or they may be discharged upon the feeding belts from a previou mechanism, such as the delivery belts of a flatwork ironer. The feeding device carries each article forward and delivers it to the travelling belts II of the longitudinal folding mechanism, the side wings of which fold the side edges inwardly around the riding plates as the article moves along with the belts. When the article reaches the cross folding mechanism,

including folding blades 51 and 15, it is engaged by one of said blades, if one cross fold is desired, or in turn by both of said blades, when two cross folds are desired, and is thus introduced to and passes through the folding rollers, which deliver it to one or the other of the plates 12, 39 along which it slides to the belts I3 which deliver it into the stacking mechanism. There it is added to the bottom of the pile being formed.

i counted with others, and the record of the count is indicated and recorded in the totalizer.

Control mec anism Since, in the specific machine illustrated in the drawings, the folding blades are actuated by electromagnet or solenoids and the operation of the stacking mechanism is controlled by another electromagnet, the control system obviously is of electric form. The circuits therefor are illustrated in Fig. 14, together with conventional illustration of the machine parts. This control system is arranged and operates as follows:

The control system shown permits several distinct folding operations, which may be individually selectively chosen by operation of the ganged switch 200 shown in Fig. 15. The said switch 200 in the wiring diagram of Fig.14 for convenience has been shown with its several elements 2lll, 202 and 203 distributed in their proper places in the various circuits but it should be understood that in actual construction and operation all three of said elements 2!, 292

dependent upon the total time for discharge of one or more of capacitances 2| I, 2l2, associated with time delay relay valve 0, and 2 I 3, associated with time delay relay valve D.

Current for charging the capacitances and operating the electronic tubes and associated rel. A single transverse fold may be made at the mid-point of the length of the article.

2. A single transverse fold may be made at any other point spaced from the mid-point of the article, the one-third point being hereinafter selected for illustration and description.

3. The article may be folded 'first at its midpoint, and then again at the mid-point of the new half length, thus accomplishing what we will term the half and quarter type of multiple fold.

4. The article may be folded first on a line spaced one-third of its length from the trailing edge, and finally on a line spaced one-third of its length from the original leading edge, thus accomplishing what we will term the one-thirdtwo-third type of transverse fold.

The general type of electronic control here illustrated, in its essential features, is similar to that illustrated and described in my said copending application, Serial No. 436,465 hereinbefore referred to, to which reference may be had if desirable or necessary. Its essential features will be here described only to an extent necessary for an understanding of the operation of the apparatus here shown.

Of the three elements of switch 200, each has three positions, left, middle and right, designated in the diagram by the reference letters L, M and R. In element 202 the L and M contacts are connected by a bridge 202a.

The parts of the folding machine, including the operating solenoids, shown in Fig. 14, require no special description, because they correspond to or are the same parts illustrated in Fig. 1, although it should be noted that the two views are reversed, with the work moving from left to right in Fig. l and from right to left in Fig. 14. In Fig. 14 the work travelling with the conveyor belts H engages in succession two trip fingers, marked I, 2, and while in contact therewith interrupts a circuit from the trip finger to an insulated conducting riding plate 32 to be referred to.

As in my copending application, the electric control system includes four electronic discharge valves marked respectively A, B, C, D. These valves are used as control devices by variation of the potential in the grid circuit to adjust it to or beyond the critical control value, thereby making the plate circuit conductive or nonconductive, a the case may be, and thus producing a delayed controlling effect in or by the plate circuit.

Electronic tubes or valves A and B are respectively in operative conjunction with the trip fingers l and 2. Each constitutes a sensitive electric relay responsive to passage of an article past said contacts. As to these tubes, when their plate circuits become conductive, tube A energizes a relay 204, moving its armatures 205, 206 to their a positions, and tube B energizes a, relay 201, moving its armatures 208, 209, 2m to their a positions. The eifect of such movements and their corelation with the entire control operation will soon appear.

As in my copending application referred to, control of the operating solenoids 61 for the folding blade 51, and 8| for the folding blade 15, is

lays is supplied from the secondaries 2 l4, 2 l 5, MB of a transformer generally designated 2", which derives its power from a conventional voltage control transformer 2l8. Secondary 2 is provided with a conventional voltage divider 2I9, secondary 2l 5 with a conventional voltage divider 220 and secondary 2H5 energizes the heater filaments of all four electronic tubes, intermediate portions of the. heating circuits being omitted for simplicity.

Time delay relay 0, when its plate circuit is conductive, energizes a, relay 219, moving its armature 220 to position a, while time delay relay valve D, when its plate circuit becomes conductive, energizes a relay 22l, moving its armature 222 to its a position.

In the arrangement shown in said copending application referred to, when it is desired to produce a single cross fold in an article at any point located upon it proportionately to its length, a

-- charged capacitance, such as the capacitance 2H in the cathode-grid circuit of discharge valve 0. is permitted to discharge at one rate when the leading edge of the article engages trip 2 and until its trailing edge engages trip i, whereupon I its discharge is continued, but at an increased rate, until the discharge is complete, whereupon the operating solenoid 61 is energized and the cross fold is produced. In such case tube D, controlling the production of a second fold, is made inoperative or ineffective by opening a manually operated normally closed switch Ma. The present control system is arranged to perform a one fold operation here precisely in the same manner as in said copending application. Again, in said copending application, the onehalf-one-quarter type of fold is produced by the use of time delay relays C, D and associated capacitances, such as 2| I, 2|3, with the rates of discharge of the capacitances 2, 2| 3 varied during the time delay period in such manner that tube C energizes solenoid 61 to produce a fold at the midpoint and tube D energizes the solenoid 8| to produce a fold at the quarter point. The completely folded article, as it is delivered to the curved plate lies upon it with the leading and trailingedges of the article superposed upon each other and lying above the cross fold at the mid-point. Again, the present control system performs that operation in exactly the same manner and by the same means as in said copending application.

As to the production of two cross folds at the one-third and two-thirds points, however, the present control system is arranged to operate differently from that of the said copending application, in that the time delay which determines the location of the second fold, controlled by the discharge of capacitance H3, is completed at a single unvarying rate and is not variable by increments during diiferent portions of the discharge, and therefore depends entirely upon the total initial charge given to capacitance 213 instead of the manner in which that charge is dissipated at two different rates.

One-third-two-thirds multiple fold For convenience the operation will first be described with reference to the production in an article already folded longitudinally in the longitudinal folding device F of two cross folds, the first produced by blade 51 at a point located one third of the total length of the article from its trailing edge and the second, produced by blade 15 at a point located one-third of the length of the article from its leading edge or two-thirds of its length from its trailing edge.

To that end switch 200 is turned to its R position and manual switch Ia. is closed, as illustrated in Fig. 14.

It is assumed that lead wires L1, La are connected to a source of current and that the circuits are all energized.

The plate circuit of valve A is nonconductive; relay 204 is deenergized and its armatures 205, 206 are in their b positions, because the grid circuit of said valve is subjected to overbias and the grid potential is above the critical control value. The biasing circuit is as follows: from the grid of valve A, through resistance 30 I, conductor 302, trip finger I, insulated conducting riding plate 32, conductor 303, resistance 304 at the voltage divider 220, conductor 305, conductor 308 and through the cathode back to the grid of valve A.

Likewise, the plate circuit of valve B is nonconductive; relay 201 is deenergized and its armatures 200, 200, M0 are in their b positions, because the grid circuit of this tube is overbiased and its potential is above the critical control value. The circuit is as follows: from the grid of valve B by way of resistance 301, conductor 308, trip finger 2, insulated conducting riding plate 32, and by way of conductors 303, resistance 304, conductor 305 and conductor 303 and through the cathode back to the grid of valve B.

At valve C the switch element 203 is in its R position and the two capacitances 2I I, 2I2 are included in the circuits in parallel, so that they act as one. These capacitances have been selected or chosen of such size that the total charge they will accept, when dissipated in the manner to be described, will produce such time delay as will cause the first folding blade 51 to be operated when a point located on the article one-third oi its total length from its trailing edge registers with the folding blade, regardless of the actual length of the article, within reasonable limits, as will appear.

These two condensers are charged by a circuit as follows: from the lower plates of said condensers by way of conductor 3| 0, armature 208 in its b position, conductor 3I I, voltage divider 220, secondary 2I5 to the point 3I2, conductor 305, conductor 3I3, and by way of the cathode and grid circuit of valve C and conductor 321 to the upper plates of the condensers. As the result of the inclusion of said capacitances in the cathodegrid circuit the grid potential of this valve also is above the critical control value, its plate circuit is nonconductive; relay 2I3 is deenergized; its armature 220 is in its 1) position and the circuit by way of conductors 3I4, 3I5 to and through the operating solenoids 61, I25 is open.

At valve D, the capacitance 2I3 alone is in circuit, but it is not charged, and its charging circuit is open, to be closed later, as will appear. Its plate circuit is conductive, relay 22I is enersized and armature 222 is in its a position, so that the circuit to operating solenoid BI by way of conductors 3I6, 3I5 is closed and the folding blade I5 is in its advanced position. But this is immaterial, as will also later appear.

Let us assume, now, that an article to be folded,

carried by the belt conveyor II, advances in the machine until its leading edge engages trip finger I. This opens the biasing circuit before described for valve A, its relay 204 i deenergized, and armatures 205, 203 move to their b positions. Nothing else happens.

- The leading edge of the article next engages trip finger 2, and because in this apparatus the two trip fingers I, 2 are spaced apart the length of the minimum length article to be folded in the machine, both trip fingers will be engaged by the article simultaneously. When the trip finger 2 is engaged, the overbiasing circuit for the grid of valve B, before described, is also opened, its plate circuit becomes conductive, relay 201 is energized, and its armatures 20B, 209, 2I0 move to their a positions. Two effects are produced, as follows:

A charging circuit is established for the capacitance 2I3 of valve D, as follows: from the lower plate of said capacitance by way of conductor 3I'I, the arm of switch 20I in its R position, conductor 3I8, armature 2I0 in its a position, conductor 3I9, voltage divider 2I3 to the point 3I2, conductor 305, conductor 320, and by way of the cathode-grid circuit of valve D back to the upper plate of capacitance 2I3. Said capacitance charges instantaneously and imposes overbias on the grid circuit, raising its potential above the critical control value. Consequently, the plate circuit of valve D becomes nonconductive, relay 22I is deenergized, armature 222 moves to its b position, and the circuit to the operating solenoid 8| opens and folding blade I5 retires ready for operating advance.

Also, a discharging circuit is completed for the capacitances 2| I, 2I2 of valve C, a follows: from the lower plates of capacitance 2I2 by way of the arm of switch 203, and from the lower plates of capacitance 2 by way of conductors 32I to the point 322, thence by way of conductor 3 I0, armature 200 in its a. position, conductor 323, resistance 324, resistance 325, resistance 323, armature 205 in its a position, and conductor 321 to the upper plates of said capacitances. Discharge of said capacitances continues at a rate dependent upon the total value of resistances 324, 325 and 320, all of which are in circuit with the capacitances. The rate of discharge is consequently low. As discharge continues the potential of the grid circuit of valve C approaches the critical control value. This effect continues until the trailing edge of the article passes trip finger I, a period of time obviously dependent upon the total length of the article (whatever that may be between the preselected minimum and maximum) reduced by the constant distance separating the trip fingers I and 2; When the trailing edge of the article passes trip finger I, the latter again engages the conducting riding plate 32, re-establishing the overbiasing circuit for valve A, whose plate circuit again becomes nonconductive, deenergizing relay 204, so that armatures 205, 200 move to their b positions. The movement of armature 205 shorts out the two resistances 325, 326

'by way of conductor 320 and the arm of switch third of its length from the trailing edge, registers with folding blade 31. At, this instant the potential of the grid circuit of valve C reaches the critical control value, its plate circuit becomes conductive, relay H9 is energized, armature 220 moved to its a position and the circuit through wires 3, 3l5 to operating solenoid 61 is closed, producing advance of the folding blade 51 to tuck the article between the first foldingarolls I3, 58, for the production of the first crossfold.

The trailing one-third of the length of the article never moves horizontally beyond the first folding blade 51, but follows a path horizontally to the left in Fig. 14 to the folding blade and thence down through the bite between the foldlng rolls I3, 58. Consequently, no matter what is the actual length of the article (variable as it is between the preselected minimum and maximum), the trailing edge always moves exactly the same distance from trip finger 2 to a position in registry with the second folding blade I5, and it will be observed that when producing a one-thirdtwo-thirds fold, the second fold must be produced when the trailing edge of the article is in said position, in registry with the folding blade 15. As the result, the time delay period for the second folding operation may begin when the trailing edge passes any predetermined point along the s path of motion, such as either at the trip finger l or the trip finger 2 or any other point, and end when the trailing edge reaches the second foldin point. That time delay readily may be determined by the amount of charge initially given to the capacitance 2I3, as determined by the voltage divider in its charging circuit, and the value of the resistance through which that charge is permitted to be dissipated.

No actual time delay is really necessary for the production of the second fold at the proper place according to the method now being described, because the trip device may be located in registry with the second folding device, so as to cause the production of the second fold simultaneously with actuation of the trip device which controls it. For example, if the first fold is produced at a point located onethird of the length of the article from its trailing edge, that part of the article which passes down through rolls i3, 58, is of double thickness and the second fold is produced as the original leading edge of the article registers with folding blade I5. So, if the trip device for the second fold is located in registry with folding blade 15, it may be sensitive to the thickness of the article, instead of to its mere presence, being actuated as the original leading edge (now the trailing edge of the double thickness portion of the article) passes the trip device.

Also, by appropriate adjustment, the second fold may be produced at a point located approximately one-third of the length of the article from its trailing edge, and also a short distance, say an inch or a fraction thereof, short of its original leading edge. In that case the second fold is produced while both parts of the doublethickness portion of the article moving into position for the second fold are still supported by rolls I3, 58, and the original first third of the article will not drop down for lack of support.

All of the foregoing is merely a matter of predetermination of the exact point where folds are desired and the selection of appropriate values of capacity and resistance, and the determination of whether time delay is necessary or not in the production of the second fold, according to the preselected,location of the trip device for controlling it.

In the present arrangement initiation of dis- I the article, begins whenthe trailing edge passes trip finger 2. The discharging circuit for capacitance U3 is as follows: from the lower plates of capacitance 213 by way of conductor 3", arm of switch 20I in its 1' position, conductor 3, armature 2l0 now in its b position, conductor 329, resistance 330, conductor 33l and conductor 332'to the upper plates of said capacitance. As soon as the capacitance N3 is fully discharged, the trailing edge of the article has registered with the folding blade 15, and at that moment the potential of the grid circuit of valve D reaches the critical control value, its plate circuit becomes conductive, relay 22l isenergized, armature 222 moves to its 'a position, and the circuit through conductors 315, M6 to operating solenoid BI is energized, causing the folding blade 15 to advance and introduce the article between the second pair of folding rolls 58, 83 for the production of the second cross fold.

The folding blade 15 remains in its advanced position until the next article to be folded engages trip 2 and recompletes the charging circuit for capacitance 2|3 before described.

In considering the circuits effective for producing the first and second folds in the onethird-two-thirds type of fold, it will also be observed that simultaneously with energization of operating solenoid for producing the first fold, the operating solenoid I25 which trips the latch mechanism controlling the lifting plate 93 also is energized. The result is that each time a first cross folding operation is initiated at the folding rolls I3, 58 a complete cycle of operations of .the lifting plate 93 is initiated and proceeds to completion, as before described.

Onehalf-one-quarter fold The same control mechanism shown in Fig. 14

vis usable for the production of the one-half-onequarter type of fold, by leaving switch 8Ia in its closed position and moving switch 200 to its intermediate position M. Description of this variation may be simplified without the necessity of retracing all circuits completely, as follows:

In this case the arm of switch 203 is on a blank ducting plate 32. The charging circuit for condenser Zll is from its lower plate through conductors 32!, 3l0, armature 208 in b position, conductor 3| l, potentiometer 220, secondary 2l5, point 3I2, conductor 305, conductor 3l3, cathode and grid of tube C to the upper plate of condenser 2H. The charging circuit for condenser H3 is from its lower plate through conductor 3" to the switch 20!, from the center point M of said switch through conductor 334, armature 209 in position, conductor I19, potentiometer 219. secondary 214, point 312, conductor I05, conductor 020, cathode and grid of tube D to the upper plate of the condenser.

When the moving article intercepts both trips 1 and 2, both of the condensers 211, 212 begin to discharge. Condenser 211 discharges through conductors 221 and 310, armature 208 in a position, conductor 323, resistors 324, 325 and 32B, armature 205 in a position, conductor 321 back to the condenser. Condenser 213 begins to discharge through conductor 311, switch 201, conductor 004, armature 200 in a .position, resistors 030 and 321, conductor 308, armature 206 in a position, conductor 032 back to condenser 213.

When the trailing edge of the article passes trip 1, relay 204 is deenergized and the armatures 205 and 200 drop to b position. These respectively short out resistors 020 and 331. The balance of the charge in condenser 211 now discharges through resistors 024 and 325, conductor 333, switch 202 and armature 205 in b position, completing the timing for the half fold, and that operation is performed. At the same time the balance of the charge in condenser 213 is being discharged through resistor 32B, conductor 339, and armature 200 in b position. When this discharge is completed the quarter fold operation is performed.

When the trailing edge of the article passes trip 2 both condensers are again recharged for the next operation, which proceeds as before when another article engages the trips.

Single cross fold at mid-point The same circuits just described for use in producing the half-quarter type of fold may be made effective for producing a single cross fold at the mid-point by simply opening the switch 01a in the circuit to the second operating solenoid 81 for folding blade '10, as a consequence of which it is impossible to produce operation of the second folding blade. However, in the system shown in Fig. 14 the arm of switch 201 accomplishes the same purpose. If the switch 200 is moved to its extreme left position the switch elements 202, 203 are substantially unaffected, because the L and M contacts of switch 202 are bridged, and each of the L and M contacts of switch 203 is a blank contact. The arm of switch 20!, however, is moved to its contact L and introduces a conductor 340 into the circuit, the operation of which is as follows: when the circuits are closed and the system made operative, a charging circuit is immediately set up for capacitance 213 as follows: from the lower plates of said capacitance by conductor 311 to the arm of switch 201, by conductor 340 to the voltage divider 21B, thence to the point 012 and by way of conductors 305 and 320 and the cathode-grid circuit of valve D to the upper plates of the capacitance. This charging circuit, it will be observed, does not include any of the armatures of the relays 204 or 201, so that contact of an article with either or both of the trip fingers 1, 2, produces no effect upon said charging circuit. The result is that during all operations of the system with the switch 200 in its L position, the capacitance 213 remains fully charged, imposing extra bias upon the grid circuit of valve D, rendering its plate circuit nonconductive and its relay 221 deenergized, so that armature 222 is in its b position and the circuit to conductor 318 for the operating solenoid 81 remains permanently open.

Values of resistances and capacities Of course, it should be understood that the theory of operation underlying the controlling circuits described herein is the same as that in my copending application before referred to. Both resistances and capacities are chosen of appropriate sizes and values to perform their respective functions. This is either a matter of mathematical calculation or, in the case of capacities, by adjusting the charge initially imposed upon each capacity, for later dissipation by increments at different rates or all at a single rate, by adjustment of one or the other of voltage dividers 218, 220 to the proper position. By such calculations and adjustments the system can be mad not only to produce folds at the mid-point alone, or of the one-half-one-quarter type or of the one-third-two-thirds type, but at any intermediate points located upon articles varying in length between a preselected minimum length and a preselected maximum length in proportion according to the total length of each article. At the same time, the control mechanism not only times the production of the fold by variation in one or two time delay periods, but it also synchronizes with the production of folds in the several articles the operation of the lifting plate of the stacking mechanism, in such manner as to provide plenty of time for each advancing article to be entirely received in the stacking mechanism prior to the elevation of its lifting plate.

Other advantages of the invention will be apparent to those skilled in the art.

What I claim is: l

1. A machine of the character described, comprising a frame, means for moving flat articles to be folded along a path, and cross folding means, including folding rollers below said path of travel, a sub-frame mounted above said path, a two-armed plate-like folding blade of generally U-form mounted in a vertical plane with its side arms extending upwardly and with the edge portions thereof guided in said sub-frame, an operating'solenoid mounted in said sub-frame between the arms of said blade, and link and lever mechanism operatively connecting the armature of said solenoid to each of the side arms of said folding blade.

2. A folding machine of the character described, comprising means for feeding flat articles varying in length alon a path, two cross folding devices spaced apart along said path, and control means therefor, including two time delay relays, each of said relays including an elec tron discharge valve and means for varying the potential of the grid cricuit thereof, means sensitive to the first of said valves for causing opera tion of the first cross folding device, means sensitive to the second of said valves for causing operation of the second cross folding device, means sensitive to the length of the articles for varying the potential of the grid circuit of the first valve by steps with approach to the critical control value at different rates during different steps of the time delay period to vary the same, and means for varying the grid potential of the second valve at a uniform rate until it reaches its critical control value for establishing a fixed time delay for the second valve.

3. A folding machine of the character described, comprising means for moving flat articles to be folded along a path, two cross folding devices spaced at intervals along said path, and control means operatively connected thereto including a single control device movable selective- 1y to either of two positions and of such form and construction as to be capable of being variously associated with said control means and variously effective upon said folding devices in its various positions, the arrangement being such that said single control device in one position renders the first folding device effective and the second folding device ineffective and in another or its positions renders both folding devices effective.

4. A folding machine of the character described, comprising means for moving flat articles to be folded along a path, two cross folding devices spaced at intervals along said path, and control means operatively connected thereto including a single control device movable selectively to any one of three positions and of such form and construction as to be capable of being variously associated with said control means and variously effective upon said folding devices in its various positions, the arrangement being such Y that said single control device in one of its positions renders one of said folding devices effective and the other ineffective and in another of its positions renders both folding devices effective to produce two cross folds in the article spaced by one proportion according to its length and in a third position renders both of said folding devices eflective to produce two cross folds in the article spaced by another proportion according to its length.

JOHN E. PRESTON, 

